If you have two pages A and B and you are direct from A->B if you dont want to come back to A using browser back button Add this code on content of page or head section of page.
Add Java script deceleration
function noBack() { window.history.forward(); }
noBack();
window.onload = noBack;
window.onpageshow = function(evt) { if (evt.persisted) noBack(); }
window.onunload = function() { void (0); }
end java script decleration
It works on IE,FF
